1. Field of the Invention
The present invention relates to a muscle training device with muscular force measurement function.
2. Description of the Background Art
Conventionally, systems or devices have been proposed which exploit a bi-articular link mechanism, such as a bi-articular arm device, and for measuring and training muscular force. Such proposals are disclosed in Japanese patent laid-open publication Nos. 2000-210272 and 2007-61137 as well as in U.S. patent application publication No. US 2008/0026923 A1 to Kadota. In such systems and devices, outputs of the muscles in the antagonistic mono- and bi-articular muscle groups of a trainee are measured with a pressure sensor. Then, a limb of a trainee is caused to exert force in a plurality of predetermined directions with his or her isometrical maximum effort, on the basis of which a hexagonally shaped output distribution chart is formed to evaluate function-based muscles of praxis.
As an actuator for driving a bi-articular link mechanism, there has also been proposed a model of a bi-articular muscle functioning to flex the arms of the creature, including the human being, which has been used in a research of the motion control of the bi-articular link mechanism. Regarding such a proposal and research, there may be listed, as T. Fujikawa et al., “Functional Coordination Control of Pairs of Antagonistic muscles”, The Japan Society of Mechanical Engineers Technical Journal (C Edition), Vol. 63, No. 607, pp. 769-776, Article No. 96-1040. In the research, in order to control rigidity and force at the distal end of an arm in the bi-articular link mechanism provided with a source of driving two joints simultaneously, it is said suitable to use a model of actuator comprising contraction and elastic elements exerting force in the contracting direction.
However, muscular force measuring and training devices in the prior art are so arranged that the members of a robot arm mounted on a limb of the trainee apply a load on the limb to measure and train the muscular force. As described above, when a load is actively applied to the trainee from a device mounted on the trainee, it is important to stop applying loads in a proper manner so as not to put the trainee in danger.
The measurement and training of muscular force cannot be attained unless the muscular force of the trainee is used to the limit. Consequently, for muscular force measurement and training devices it is significantly important to stop applying loads by appropriately determining the limit of the muscular force of the trainee. It is, however, difficult to correctly determine the limit of the muscular force of the trainee.
With muscular force training devices, training of muscles of praxis can be performed effectively, whereas the trainee grows easily tired because of the comparatively monotonic exercise. It is thus considered that practical exercise, such as bike riding, is employed so that the trainee can enjoy training.
For this, it has been proposed that a pseudo-bicycle type muscular force training device is used to change a load according to the angle of rotation to train specified muscles. However, since the muscular force training device of pseudo-bicycle type maintains for a comparatively short period of time a situation where a load is applied to the target muscle, compared with that in the entire exercise, it is difficult to achieve effective training.
Further, the muscular force measurement and training devices are so arranged that a load is applied to a limb of the trainee from the members of a robot arm mounted on the limb to perform measurement and training of the muscular force. Due to this, the sum of a load applied by the device, the own weight of the movable parts of the device and the own weight of the limb of the trainee become a load on his or her limb. Consequently, a load applied to the limb of the trainee cannot correctly be controlled unless the influence of the own weight of the movable parts of the device and the weight of his or her limb is taken into account.